Silicone

DOWSIL (Dow Corning) 890-SL Silicone Expansion Joint Sealant — Residential & Commercial Joint Sealing by Sealtechs

Expansion joints are built into concrete for one reason: concrete moves. Heat, cold, moisture, and settling cause slabs to expand and contract. When those joints are left open—or the old filler fails—they become a direct entry point for water intrusion, debris buildup, weeds, and long-term sub-base damage.

That’s why Sealtechs seals joints using professional-grade systems, including DOWSIL™ 890-SL (formerly Dow Corning 890-SL)—a high-performance self-leveling silicone joint sealant designed specifically for horizontal concrete and concrete-to-asphalt joints.

We install 890-SL on both residential and commercial projects, helping keep concrete clean, protected, and looking sharp.

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Why Sealtechs Uses DOWSIL 890-SL

Self-leveling finish for clean, consistent joints

DOWSIL 890-SL is self-leveling, meaning it flows into the joint and settles smooth for a uniform appearance—especially valuable on older slabs where joints aren’t perfectly uniform.

Designed for movement in pavement-style joints

Expansion joints must flex. 890-SL is designed for pavement joint movement and is built to handle the push-pull of seasonal shifting.

Strong exterior durability (UV + weather exposure)

This product is intended for outdoor conditions, where sun and weather can destroy weaker sealants over time.

Great for concrete-to-concrete and concrete-to-asphalt joints

It’s commonly used in applications like driveways, sidewalks, approaches, and commercial flatwork where concrete meets asphalt.

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Where We Install 890-SL (Residential + Commercial)

Residential

• Driveway expansion joints
• Sidewalk joints
• Walkways and patios
• Garage approaches and apron transitions

Commercial

• Parking lots and drive lanes
• Sidewalks and storefront approaches
• Warehouse/apron areas (where applicable)
• Concrete-to-asphalt transitions and high-traffic joints

If it’s a horizontal joint that needs clean lines and long-term performance, 890-SL is often a top-tier option.

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The Sealtechs Installation Standard (What Makes It Last)

A premium sealant still fails if the joint isn’t prepared properly. Sealtechs focuses on the full system, not just squeezing product into a crack:

1. Removal & clean-out
   We remove old sealant, failed fillers, vegetation, and debris to expose sound joint walls.
2. Proper depth control
   We install a backer rod (when required) to control sealant depth and help the joint perform correctly as it moves.
3. Sealant installation
   We install DOWSIL 890-SL in the joint and allow it to self-level for a smooth, consistent finish.
4. Cure awareness
   We advise customers on cure/return-to-service expectations based on temperature, humidity, and joint size.

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Why Sealing Expansion Joints Matters

Sealing joints isn’t just about looks (though it does look a lot better). It helps prevent the most common concrete problems:

• Protects the sub-base by reducing water intrusion and washout
• Helps prevent weeds by eliminating open pockets for soil and growth
• Reduces pest activity by removing gaps that insects use as travel routes
• Supports joint edge protection by reducing debris packing and breakdown
• Improves curb appeal with clean, professional joint lines

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Important Note: 890-SL is for horizontal joints

Because it’s self-leveling, DOWSIL 890-SL is typically used for horizontal/pavement joints, not vertical wall joints (vertical joints require non-sag sealants).

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Sealtechs: Professional Joint Sealing for Homes & Businesses

Whether it’s a homeowner driveway or a commercial parking lot, expansion joints should be sealed with the right product and the right prep. Sealtechs installs joint sealant systems—like DOWSIL 890-SL—so your concrete stays protected, clean, and finished.